Energy and work are both measured in joules in the International System of Units (SI). This similarity in measurement arises from the close relationship between the two concepts in physics.
Work is defined as the process of energy transfer when an object is displaced by a force. Mathematically, work (W) is represented by the formula:
W = F × d × cos(θ)
where F is the force applied, d is the distance moved by the object, and θ is the angle between the force and the direction of movement. The unit of force is the newton (N), and distance is measured in meters (m). Since 1 joule equals 1 newton-meter (1 J = 1 N·m), the units of work and energy effectively become identical.
Energy, on the other hand, is the capacity to perform work. When energy is converted from one form to another, or when it is used to do work, it is also expressed in joules. Therefore, energy serves as the source that allows work to be done, and both are tied together through this fundamental relationship.
In summary, the reason energy and work share the same units is that they describe processes involving force and motion and they directly relate to one another in the physical world.